//: net/mindview/util/Directory.java
// Produce a sequence of File objects that match a
// regular expression in either a local directory,
// or by walking a directory tree.
package u.can.i.up.gearmanimpl.common;

import java.util.regex.*;
import java.io.*;
import java.util.*;

public final class Directory {

	public static File[] local(File dir, final String regex) {
		return dir.listFiles(new FilenameFilter() {
			private Pattern pattern = Pattern.compile(regex);

			public boolean accept(File dir, String name) {
				return pattern.matcher(new File(name).getName()).matches();
			}
		});
	}

	public static File[] local(String path, final String regex) { // Overloaded
		return local(new File(path), regex);
	}

	// A two-tuple for returning a pair of objects:
	public static class TreeInfo implements Iterable<File> {
		public List<File> files = new ArrayList<File>();
		public List<File> dirs = new ArrayList<File>();

		// The default iterable element is the file list:
		public Iterator<File> iterator() {
			return files.iterator();
		}

		void addAll(TreeInfo other) {
			files.addAll(other.files);
			dirs.addAll(other.dirs);
		}

		public String toString() {
			return "dirs: " + PPrint.pformat(dirs) + "\n\nfiles: " + PPrint.pformat(files);
		}
	}

	public static TreeInfo walk(String start, String regex) { // Begin recursion
		return recurseDirs(new File(start), regex);
	}

	public static TreeInfo walk(File start, String regex) { // Overloaded
		return recurseDirs(start, regex);
	}

	public static TreeInfo walk(File start) { // Everything
		return recurseDirs(start, ".*");
	}

	public static TreeInfo walk(String start) {
		return recurseDirs(new File(start), ".*");
	}

	static TreeInfo recurseDirs(File startDir, String regex) {
		TreeInfo result = new TreeInfo();
		for (File item : startDir.listFiles()) {
			if (item.isDirectory()) {
				result.dirs.add(item);
				result.addAll(recurseDirs(item, regex));
			} else // Regular file
			if (item.getName().matches(regex))
				result.files.add(item);
		}
		return result;
	}

	public static void ensureDir(File dir) {
		if (dir.exists() && dir.isDirectory()) {
			return;
		}
		if (!dir.getParentFile().exists()) {
			ensureDir(dir.getParentFile());
		}
		if (dir.isFile()) {
			dir.delete();
		}
		dir.mkdir();
	}

	// Simple validation test:
	public static void main(String[] args) {
		if (args.length == 0)
			System.out.println(walk(".", "PPrint.java"));
		else
			for (String arg : args)
				System.out.println(walk(arg));
	}
} // /:~
